Okay, I re-did the 'omit from surface' set to surface. Every parameter was and is at zero. The particles still sit on the plane when it's flat, but then get above and below the plane where it curves. For example on what is a hill, the particles follow the general curve of the hill, but take a shortcut underneath it.
I searched old posts and found where Sean suggested as part of a slightly different process to rebuild the NURBS surface, which I did. No change.
Chris Smith
http://www.sugarfilmproduction.com
